[clang-tidy] Replace deprecated std::ios_base aliases

[andobence]

Summary

This check warns the uses of the deprecated member types of std::ios_base
and replaces those that have a non-deprecated equivalent.

[JonasToth]

Hi andobence,

thank you for the contribution. The check looks very good!
Please add it to the release notes and synchronize the first line of the doc with the short sentence in the release notes describing what this check does.

clang-tidy/modernize/DeprecatedIosBaseAliasesCheck.h

21

I I think you can write non-deprecated without the whitespace.

test/clang-tidy/modernize-deprecated-ios-base-aliases.cpp

15

That format looks weird. Could you please run clang-format over the test as well?

[JonasToth]

clang-tidy/modernize/DeprecatedIosBaseAliasesCheck.cpp

35

Which standard supplies the replacement functionality? e.g. for C++98 the warning is probably not relevant because there is no way to replace the deprecated types, but for C++17 it is possible.

[andobence]

Fixed everything mentioned in comments.

[andobence]

clang-tidy/modernize/DeprecatedIosBaseAliasesCheck.cpp

35

C++98 already has them, these types has been deprecated since draft N0785 from 1995.

[JonasToth]

LG from my side, please rebase that patch on top of master. Currently the Release Notes would conflict (and please sort the release note alphabetically).

If the other reviewers do not say anything within a reasonable time it can be committed. Do you have commit rights?

[JonasToth]

And i forgot: Could you please run this over a real code base, if you know one that actually uses these types?
I assume not so many code bases actually use these.

[alexfh]

LG once other comments are addressed.

[JonasToth]

from my side is nothing outstanding, do you need someone to commit on your behalf?

[andobence]

Rebased on top of master.
I don't have commit rights.

[JonasToth]

Commited in https://reviews.llvm.org/rL343848.
Thank you for the patch!

clang-tidy/modernize/CMakeLists.txt

 set(LLVM_LINK_COMPONENTS support)
 
 add_clang_library(clangTidyModernizeModule
   AvoidBindCheck.cpp
   ConcatNestedNamespacesCheck.cpp
   DeprecatedHeadersCheck.cpp
+  DeprecatedIosBaseAliasesCheck.cpp
   LoopConvertCheck.cpp
   LoopConvertUtils.cpp
   MakeSharedCheck.cpp
   MakeSmartPtrCheck.cpp
   MakeUniqueCheck.cpp
   ModernizeTidyModule.cpp
   PassByValueCheck.cpp
   RawStringLiteralCheck.cpp

clang-tidy/modernize/DeprecatedIosBaseAliasesCheck.h

+//===--- DeprecatedIosBaseAliasesCheck.h - clang-tidy------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_MODERNIZE_DEPRECATEDIOSBASEALIASESCHECK_H
+#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_MODERNIZE_DEPRECATEDIOSBASEALIASESCHECK_H
+
+#include "../ClangTidy.h"
+
+namespace clang {
+namespace tidy {
+namespace modernize {
+
+/// This check warns the uses of the deprecated member types of ``std::ios_base``
+/// and replaces those that have a non-deprecated equivalent.
+///
+/// For the user-facing documentation see:
+/// http://clang.llvm.org/extra/clang-tidy/checks/modernize-deprecated-ios-base-aliases.html
+class DeprecatedIosBaseAliasesCheck : public ClangTidyCheck {
+public:
+  DeprecatedIosBaseAliasesCheck(StringRef Name, ClangTidyContext *Context)
+      : ClangTidyCheck(Name, Context) {}
+  void registerMatchers(ast_matchers::MatchFinder *Finder) override;
+  void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
+};
+
+} // namespace modernize
+} // namespace tidy
+} // namespace clang
+
+#endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_MODERNIZE_DEPRECATEDIOSBASEALIASESCHECK_H

clang-tidy/modernize/DeprecatedIosBaseAliasesCheck.cpp

+//===--- DeprecatedIosBaseAliasesCheck.cpp - clang-tidy--------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "DeprecatedIosBaseAliasesCheck.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+
+using namespace clang::ast_matchers;
+
+namespace clang {
+namespace tidy {
+namespace modernize {
+
+static const std::array<StringRef, 5> DeprecatedTypes = {
+    "::std::ios_base::io_state",  "::std::ios_base::open_mode",
+    "::std::ios_base::seek_dir",  "::std::ios_base::streamoff",
+    "::std::ios_base::streampos",
+};
+
+static const llvm::StringMap<StringRef> ReplacementTypes = {
+    {"io_state", "iostate"},
+    {"open_mode", "openmode"},
+    {"seek_dir", "seekdir"}};
+
+void DeprecatedIosBaseAliasesCheck::registerMatchers(MatchFinder *Finder) {
+  // Only register the matchers for C++; the functionality currently does not
+  // provide any benefit to other languages, despite being benign.
+  if (!getLangOpts().CPlusPlus)
+    return;
+
+  auto IoStateDecl = typedefDecl(hasAnyName(DeprecatedTypes)).bind("TypeDecl");
+  auto IoStateType =
+      qualType(hasDeclaration(IoStateDecl), unless(elaboratedType()));
+
+  Finder->addMatcher(typeLoc(loc(IoStateType)).bind("TypeLoc"), this);
+}
+
+void DeprecatedIosBaseAliasesCheck::check(
+    const MatchFinder::MatchResult &Result) {
+  SourceManager &SM = *Result.SourceManager;
+
+  const auto *Typedef = Result.Nodes.getNodeAs<TypedefDecl>("TypeDecl");
+  StringRef TypeName = Typedef->getName();
+  bool HasReplacement = ReplacementTypes.count(TypeName);
+
+  const auto *TL = Result.Nodes.getNodeAs<TypeLoc>("TypeLoc");
+  SourceLocation IoStateLoc = TL->getBeginLoc();
+
+  // Do not generate fixits for matches depending on template arguments and
+  // macro expansions.
+  bool Fix = HasReplacement && !TL->getType()->isDependentType();
+  if (IoStateLoc.isMacroID()) {
+    IoStateLoc = SM.getSpellingLoc(IoStateLoc);
+    Fix = false;
+  }
+
+  SourceLocation EndLoc = IoStateLoc.getLocWithOffset(TypeName.size() - 1);
+
+  if (HasReplacement) {
+    auto FixName = ReplacementTypes.lookup(TypeName);
+    auto Builder = diag(IoStateLoc, "'std::ios_base::%0' is deprecated; use "
+                                    "'std::ios_base::%1' instead")
+                   << TypeName << FixName;
+
+    if (Fix)
+      Builder << FixItHint::CreateReplacement(SourceRange(IoStateLoc, EndLoc),
+                                              FixName);
+  } else
+    diag(IoStateLoc, "'std::ios_base::%0' is deprecated") << TypeName;
+}
+
+} // namespace modernize
+} // namespace tidy
+} // namespace clang

clang-tidy/modernize/ModernizeTidyModule.cpp

 //===--- ModernizeTidyModule.cpp - clang-tidy -----------------------------===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 
 #include "../ClangTidy.h"
 #include "../ClangTidyModule.h"
 #include "../ClangTidyModuleRegistry.h"
 #include "AvoidBindCheck.h"
 #include "ConcatNestedNamespacesCheck.h"
 #include "DeprecatedHeadersCheck.h"
+#include "DeprecatedIosBaseAliasesCheck.h"
 #include "LoopConvertCheck.h"
 #include "MakeSharedCheck.h"
 #include "MakeUniqueCheck.h"
 #include "PassByValueCheck.h"
 #include "RawStringLiteralCheck.h"
 #include "RedundantVoidArgCheck.h"
 #include "ReplaceAutoPtrCheck.h"
 #include "ReplaceRandomShuffleCheck.h"

 class ModernizeModule : public ClangTidyModule {
 public:
   void addCheckFactories(ClangTidyCheckFactories &CheckFactories) override {
     CheckFactories.registerCheck<AvoidBindCheck>("modernize-avoid-bind");
     CheckFactories.registerCheck<ConcatNestedNamespacesCheck>(
         "modernize-concat-nested-namespaces");
     CheckFactories.registerCheck<DeprecatedHeadersCheck>(
         "modernize-deprecated-headers");
+    CheckFactories.registerCheck<DeprecatedIosBaseAliasesCheck>(
+        "modernize-deprecated-ios-base-aliases");
     CheckFactories.registerCheck<LoopConvertCheck>("modernize-loop-convert");
     CheckFactories.registerCheck<MakeSharedCheck>("modernize-make-shared");
     CheckFactories.registerCheck<MakeUniqueCheck>("modernize-make-unique");
     CheckFactories.registerCheck<PassByValueCheck>("modernize-pass-by-value");
     CheckFactories.registerCheck<RawStringLiteralCheck>(
         "modernize-raw-string-literal");
     CheckFactories.registerCheck<RedundantVoidArgCheck>(
         "modernize-redundant-void-arg");

docs/ReleaseNotes.rst

- New :doc:`abseil-str-cat-append
   ``absl::StrAppend()`` should be used instead.
 
 - New :doc:`modernize-concat-nested-namespaces
   <clang-tidy/checks/modernize-concat-nested-namespaces>` check.
 
   Checks for uses of nested namespaces in the form of
   ``namespace a { namespace b { ... }}`` and offers change to
   syntax introduced in C++17 standard: ``namespace a::b { ... }``.
   
+- New :doc:`modernize-deprecated-ios-base-aliases
+  <clang-tidy/checks/modernize-deprecated-ios-base-aliases>` check.
+
+  This check warns the uses of the deprecated member types of ``std::ios_base``
+  and replaces those that have a non-deprecated equivalent.
+
 - New :doc:`readability-magic-numbers
   <clang-tidy/checks/readability-magic-numbers>` check.
 
   Detects usage of magic numbers, numbers that are used as literals instead of
   introduced via constants or symbols.
 
 Improvements to include-fixer
 -----------------------------
 
 The improvements are...
 
 Improvements to modularize
 --------------------------
 
 The improvements are...

docs/clang-tidy/checks/list.rst

.. toctree::
    misc-unconventional-assign-operator
    misc-uniqueptr-reset-release
    misc-unused-alias-decls
    misc-unused-parameters
    misc-unused-using-decls
    modernize-avoid-bind
    modernize-concat-nested-namespaces
    modernize-deprecated-headers
+   modernize-deprecated-ios-base-aliases
    modernize-loop-convert
    modernize-make-shared
    modernize-make-unique
    modernize-pass-by-value
    modernize-raw-string-literal
    modernize-redundant-void-arg
    modernize-replace-auto-ptr
    modernize-replace-random-shuffle

docs/clang-tidy/checks/modernize-deprecated-ios-base-aliases.rst

+.. title:: clang-tidy - modernize-deprecated-ios-base-aliases
+
+modernize-deprecated-ios-base-aliases
+=====================================
+
+This check warns the uses of the deprecated member types of ``std::ios_base``
+and replaces those that have a non-deprecated equivalent.
+
+===================================  ===========================
+Deprecated member type               Replacement
+===================================  ===========================
+``std::ios_base::io_state``          ``std::ios_base::iostate``
+``std::ios_base::open_mode``         ``std::ios_base::openmode``
+``std::ios_base::seek_dir``          ``std::ios_base::seekdir``
+``std::ios_base::streamoff``          
+``std::ios_base::streampos``         
+===================================  ===========================

test/clang-tidy/modernize-deprecated-ios-base-aliases.cpp

+// RUN: %check_clang_tidy %s modernize-deprecated-ios-base-aliases %t
+
+namespace std {
+class ios_base {
+public:
+  typedef int io_state;
+  typedef int open_mode;
+  typedef int seek_dir;
+
+  typedef int streampos;
+  typedef int streamoff;
+};
+
+template <class CharT>
+class basic_ios : public ios_base {
+};
+} // namespace std
+
+// Test function return values (declaration)
+std::ios_base::io_state f_5();
+// CHECK-MESSAGES: :[[@LINE-1]]:16: warning: 'std::ios_base::io_state' is deprecated; use 'std::ios_base::iostate' instead [modernize-deprecated-ios-base-aliases]
+// CHECK-FIXES: std::ios_base::iostate f_5();
+
+// Test function parameters.
+void f_6(std::ios_base::open_mode);
+// CHECK-MESSAGES: :[[@LINE-1]]:25: warning: 'std::ios_base::open_mode' is deprecated
+// CHECK-FIXES: void f_6(std::ios_base::openmode);
+void f_7(const std::ios_base::seek_dir &);
+// CHECK-MESSAGES: :[[@LINE-1]]:31: warning: 'std::ios_base::seek_dir' is deprecated
+// CHECK-FIXES: void f_7(const std::ios_base::seekdir &);
+
+// Test on record type fields.
+struct A {
+  std::ios_base::io_state field;
+  // CHECK-MESSAGES: :[[@LINE-1]]:18: warning: 'std::ios_base::io_state' is deprecated
+  // CHECK-FIXES: std::ios_base::iostate field;
+
+  typedef std::ios_base::io_state int_ptr_type;
+  // CHECK-MESSAGES: :[[@LINE-1]]:26: warning: 'std::ios_base::io_state' is deprecated
+  // CHECK-FIXES: typedef std::ios_base::iostate int_ptr_type;
+};
+
+struct B : public std::ios_base {
+  io_state a;
+  // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: 'std::ios_base::io_state' is deprecated
+  // CHECK-FIXES: iostate a;
+};
+
+struct C : public std::basic_ios<char> {
+  io_state a;
+  // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: 'std::ios_base::io_state' is deprecated
+  // CHECK-FIXES: iostate a;
+};
+
+void f_1() {
+  std::ios_base::io_state a;
+  // CHECK-MESSAGES: :[[@LINE-1]]:18: warning: 'std::ios_base::io_state' is deprecated
+  // CHECK-FIXES: std::ios_base::iostate a;
+
+  // Check that spaces aren't modified unnecessarily.
+  std :: ios_base :: io_state b;
+  // CHECK-MESSAGES: :[[@LINE-1]]:22: warning: 'std::ios_base::io_state' is deprecated
+  // CHECK-FIXES: std :: ios_base :: iostate b;
+
+  // Test construction from a temporary.
+  std::ios_base::io_state c = std::ios_base::io_state{};
+  // CHECK-MESSAGES: :[[@LINE-1]]:18: warning: 'std::ios_base::io_state' is deprecated
+  // CHECK-MESSAGES: :[[@LINE-2]]:46: warning: 'std::ios_base::io_state' is deprecated
+  // CHECK-FIXES: std::ios_base::iostate c = std::ios_base::iostate{};
+
+  typedef std::ios_base::io_state alias1;
+  // CHECK-MESSAGES: :[[@LINE-1]]:26: warning: 'std::ios_base::io_state' is deprecated
+  // CHECK-FIXES: typedef std::ios_base::iostate alias1;
+  alias1 d(a);
+
+  using alias2 = std::ios_base::io_state;
+  // CHECK-MESSAGES: :[[@LINE-1]]:33: warning: 'std::ios_base::io_state' is deprecated
+  // CHECK-FIXES: using alias2 = std::ios_base::iostate;
+  alias2 e;
+
+  // Test pointers.
+  std::ios_base::io_state *f;
+  // CHECK-MESSAGES: :[[@LINE-1]]:18: warning: 'std::ios_base::io_state' is deprecated
+  // CHECK-FIXES: std::ios_base::iostate *f;
+
+  // Test 'static' declarations.
+  static std::ios_base::io_state g;
+  // CHECK-MESSAGES: :[[@LINE-1]]:25: warning: 'std::ios_base::io_state' is deprecated
+  // CHECK-FIXES: static std::ios_base::iostate g;
+
+  // Test with cv-qualifiers.
+  const std::ios_base::io_state h(0);
+  // CHECK-MESSAGES: :[[@LINE-1]]:24: warning: 'std::ios_base::io_state' is deprecated
+  // CHECK-FIXES: const std::ios_base::iostate h(0);
+  volatile std::ios_base::io_state i;
+  // CHECK-MESSAGES: :[[@LINE-1]]:27: warning: 'std::ios_base::io_state' is deprecated
+  // CHECK-FIXES: volatile std::ios_base::iostate i;
+  const volatile std::ios_base::io_state j(0);
+  // CHECK-MESSAGES: :[[@LINE-1]]:33: warning: 'std::ios_base::io_state' is deprecated
+  // CHECK-FIXES: const volatile std::ios_base::iostate j(0);
+
+  // Test auto and initializer-list.
+  auto k = std::ios_base::io_state{};
+  // CHECK-MESSAGES: :[[@LINE-1]]:27: warning: 'std::ios_base::io_state' is deprecated
+  // CHECK-FIXES: auto k = std::ios_base::iostate{};
+
+  std::ios_base::io_state l{std::ios_base::io_state()};
+  // CHECK-MESSAGES: :[[@LINE-1]]:18: warning: 'std::ios_base::io_state' is deprecated
+  // CHECK-MESSAGES: :[[@LINE-2]]:44: warning: 'std::ios_base::io_state' is deprecated
+  // CHECK-FIXES: std::ios_base::iostate l{std::ios_base::iostate()};
+
+  // Test temporaries.
+  std::ios_base::io_state();
+  // CHECK-MESSAGES: :[[@LINE-1]]:18: warning: 'std::ios_base::io_state' is deprecated
+  // CHECK-FIXES: std::ios_base::iostate();
+
+  // Test inherited type usage
+  std::basic_ios<char>::io_state m;
+  // CHECK-MESSAGES: :[[@LINE-1]]:25: warning: 'std::ios_base::io_state' is deprecated
+  // CHECK-FIXES: std::basic_ios<char>::iostate m;
+
+  std::ios_base::streampos n;
+  // CHECK-MESSAGES: :[[@LINE-1]]:18: warning: 'std::ios_base::streampos' is deprecated [modernize-deprecated-ios-base-aliases]
+
+  std::ios_base::streamoff o;
+  // CHECK-MESSAGES: :[[@LINE-1]]:18: warning: 'std::ios_base::streamoff' is deprecated [modernize-deprecated-ios-base-aliases]
+}
+
+// Test without the nested name specifiers.
+void f_2() {
+  using namespace std;
+
+  ios_base::io_state a;
+  // CHECK-MESSAGES: :[[@LINE-1]]:13: warning: 'std::ios_base::io_state' is deprecated
+  // CHECK-FIXES: ios_base::iostate a;
+}
+
+// Test messing-up with macros.
+void f_4() {
+#define MACRO_1 std::ios_base::io_state
+  // CHECK-MESSAGES: :[[@LINE-1]]:32: warning: 'std::ios_base::io_state' is deprecated
+  MACRO_1 a;
+
+#define MACRO_2 io_state
+  // CHECK-MESSAGES: :[[@LINE-1]]:17: warning: 'std::ios_base::io_state' is deprecated
+  std::ios_base::MACRO_2 b;
+
+#define MACRO_3 std::ios_base
+  MACRO_3::io_state c;
+  // CHECK-MESSAGES: :[[@LINE-1]]:12: warning: 'std::ios_base::io_state' is deprecated
+
+#define MACRO_4(type) type::io_state
+  // CHECK-MESSAGES: :[[@LINE-1]]:29: warning: 'std::ios_base::io_state' is deprecated
+  MACRO_4(std::ios_base) d;
+
+#undef MACRO_1
+#undef MACRO_2
+#undef MACRO_3
+#undef MACRO_4
+}
+
+// Test function return values (definition).
+std::ios_base::io_state f_5()
+// CHECK-MESSAGES: :[[@LINE-1]]:16: warning: 'std::ios_base::io_state' is deprecated
+// CHECK-FIXES: std::ios_base::iostate f_5()
+{
+  // Test constructor.
+  return std::ios_base::io_state(0);
+  // CHECK-MESSAGES: :[[@LINE-1]]:25: warning: 'std::ios_base::io_state' is deprecated
+  // CHECK-FIXES: return std::ios_base::iostate(0);
+}
+
+// Test that other aliases with same name aren't replaced
+struct my_ios_base {
+  typedef int io_state;
+};
+
+namespace ns_1 {
+struct my_ios_base2 {
+  typedef int io_state;
+};
+} // namespace ns_1
+
+void f_8() {
+  my_ios_base::io_state a;
+
+  ns_1::my_ios_base2::io_state b;
+}
+
+// Test templates
+template <typename X>
+void f_9() {
+  typename std::basic_ios<X>::io_state p;
+  // CHECK-MESSAGES: :[[@LINE-1]]:31: warning: 'std::ios_base::io_state' is deprecated
+  typename std::ios_base::io_state q;
+  // CHECK-MESSAGES: :[[@LINE-1]]:27: warning: 'std::ios_base::io_state' is deprecated
+  // CHECK-FIXES: typename std::ios_base::iostate q;
+}
+
+template <typename T>
+void f_10(T arg) {
+  T x(arg);
+}
+
+template <typename T>
+void f_11() {
+  typename T::io_state x{};
+  // CHECK-MESSAGES: :[[@LINE-1]]:15: warning: 'std::ios_base::io_state' is deprecated
+}
+
+template <typename T>
+struct D : std::ios_base {
+  io_state a;
+  // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: 'std::ios_base::io_state' is deprecated
+  // CHECK-FIXES: iostate a;
+
+  typename std::basic_ios<T>::io_state b;
+  // CHECK-MESSAGES: :[[@LINE-1]]:31: warning: 'std::ios_base::io_state' is deprecated
+};
+
+template <typename T>
+struct E {
+  T t;
+};
+
+void f_12() {
+  f_9<char>();
+
+  f_10<std::ios_base::io_state>(0);
+  // CHECK-MESSAGES: :[[@LINE-1]]:23: warning: 'std::ios_base::io_state' is deprecated
+  // CHECK-FIXES: f_10<std::ios_base::iostate>(0);
+
+  f_11<std::ios_base>();
+  D<char> d;
+
+  E<std::ios_base::io_state> e;
+  // CHECK-MESSAGES: :[[@LINE-1]]:20: warning: 'std::ios_base::io_state' is deprecated
+  // CHECK-FIXES: E<std::ios_base::iostate> e;
+}